Switching to Symfony for Drupal 8 means changing how you add new functionality to your site. Many of these are implemented as Plugins, for instance: Blocks, Fields, Widget, REST resources, andImage effects. In this session you will learn why Plugins exist and how to implement your own. We’ll discuss the various interfaces, the Plugin Manager and discovery. We’ll also touch on dependency injection and all the other systems you need to know to write your own extensions to Drupal 8.